Mandrel bar guide



H. HEETKAMP MANDREL BAR GUIDE Filed Sept. .4. 1930 2 Sheets-Sheet l Inventor Attorney.

' H. HEETKAMP 3,874,992

MANDREL BAR GUIDE Aug. 30, 1932.

2 Sheets-Sheet 2 Filed Sept. 4. 1930 J 4 34 3 il in lmuinimun-m Hum:mn ui ummlnml uluugigl Inventor w. E, W: .lttorrwy.

Patented Au 30, 1932 -rra stars PATNT; FFHCE TKAMI, F DUISBURG, GERMANY, ASSIGNOR TO DEMAG AKTIENGESEIiL- SCHAFT, 0F DUISBURG, GERMANY MANDREL BAR GUIDE Application filed September 4, 1930, Serial No.

lhis invention relates to a device for guiding the mandrel bar of tube push benches in which the carriers of pivoted -mandrel bar supports are removably inserted between the drawing rings in the bed of the push bench. Such guiding devices have already become known, i. e. so designed in a manner that the pivoted supports are maintained in the supporting position either under spring m action, or by pneumatic or hydraulic pressure so that they may turn aside, in accordance with requirements of the forward movement of the mandrel bar.

Such devices are imperfect inasmuch as, 3 owing to the strong pressure of the supports to the mandrel bar, the bar must overcome considerable friction while being guided.

In order to avoid this disadvantage of the guide devices that have hitherto become 29 known it is proposed, according to the invention, to provide two or more pivoted supporting levers embracing the mandrel bar, whlch swing into the supporting positlon solely owin to their own weight, and which are locke by a pawl against an accidental displacement, the releasing of the supporting levers being effected by means of a stop lever arranged in front in such a manner that the work piece moves the pawl out of its lock ing position, and that, subsequently, the work piece also forces the supportlng levers out of its path.

In the accompan 'ng drawings, byway of example, an embodYi ment of the invention is shown diagrammatically,

Fig. 1 showing the apparatus in longitudinal section,

Fig. 2 an axial View,

Fig. 3 a sectional plan in part'of a carrier and a supporting lever, while 1F ig. 4 shows, to a smaller scale, a longitudinal section of the ring bed into which several guiding devices are inserted.

The ring bed 1 is provided, in the wellknown manner, with a great number of grooves 2 into which, likewise in a known manner, guide devices for the mandrel bar are inserted between the draw rings.

The guide device according to. the invenac tion comprises a ring-like body 4 which, as

479,784, and in Germany September 12, 1929.

is shown in Figs. 1, 2 and 4, is inserted between the draw rings 3 into a groove 2 of the ring bed 1. Freely-swinging levers 6, revolvable around bolts 5 on the body 4 and having guide faces turned towards the mandrel bar, are provided to embracein their working position, with their recesses 7, the mandrel bar 8, thus affording guidance to the latter. Between the projections 9 of the levers 6 projecting beyond the bolts 5 a pawl 10 is seated when the levers are in their working position, the pawl being a shank of the double lever 10, 11. The latter is revolvable around the pivot pin 12, and the shank 11 is adapted to serve as a stop, being disposed in the path of the work piece. A counterweight 13 carried by the lever 10, 11 tends to maintain the said lever in the locking position, as shown in full lines in Figs. 1 and 2.

The work piece pushed through the draw rings with the aid of the mandrel bar 8, in its axial feed movement, first touches the stop lever 11 and pushes it back (compare the position indicated by a dotted line in Fig. 1) in such a manner that the pawl 10 releases the two projections 9 of the levers 6. Consequently, the work piece can also make the levers 6 turn aside. As soon as the stop lever 11, in the further forward movement of the mandrel bar, is out of reach of the work piece 14, the lever 10, 11, under the influence of the counter-weight 13, swings back into the position shown by full lines, and thus locks the levers 6' in their working positions.

What I claim is:

1. In a tube push bench provided with a bed transversely grooved to receive draw rings, a plurality of mandrel bar support carriers adapted to be removably positioned in said bed between said draw rings, a plurality of pivoted mandrel bar supports carried by each of said carriers and adapted to swing into the working position under their own .weight, and locking devices for said mandrel bar supports also mounted on said carriers and disposed partly in the path of Eli? the work and adapted to be moved out of such path to unlock the mandrel bar supports to allow the mandrel bar supports to separate to allow the work to pass.

"bed transversely grooved rings, 'a plurality of mandrel bar support 2. In a tube push bench provided with a to receive draw.

carriers adapted to be removahly positioned in said bed between said draw rings, a plurality of levers servin as mandrel bar supports pivoted intermediate their lengths upon said carriers and adapted to swing into the working position under their own weight and a stop lever pivoted upon each of sai carriers and adapted to extend with one-part into a locking position with reference to the mandrel bar support levers carried by said carrier and with another part into the path of the work, to be oscillated by the work for the release of said mandrel bar support levers so that they may be pressed aside y the passing work.

HEINRICH HEETIQMP. 

